wp_send_new_user_notifications() WP 4.4.0

Initiates email notifications related to the creation of new users.

Notifications are sent both to the site admin and to the newly created user.

No Hooks.

Return

Nothing (null).

Usage

wp_send_new_user_notifications( $user_id, $notify );

$user_id(int) (required)

ID of the newly created user.

$notify(string)

Type of notification that should happen. Accepts 'admin' or an empty string (admin only), 'user', or 'both' (admin and user).
Default: 'both'

Code of wp send new user notifications: wp-includes/user.php ^{WP 5.2.1}

<?php
function wp_send_new_user_notifications( $user_id, $notify = 'both' ) {
	wp_new_user_notification( $user_id, null, $notify );
}